A communication module includes a laser driving unit (LDU) and one or more multifunction illumination units. The one or more multifunction illumination units are be coupled to the LDU with an electrical connection and configured to transmit both electrical power and data.

An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The quantum well active layer is doped with 0.3 to 1×10.sup.18/cm.sup.3 of n-type impurity.

A laser comprising a laser cavity formed by a first optical reflector, a gain region, a second optical reflector having a plurality of reflection peaks, and at least one optically active region. The first mirror may be a DBR or comb mirror and the second mirror may be a comb mirror. The spectral reflectance of the second optical reflector is adjusted at least partially based on an electric signal received form the optically active region such that only one reflection peak is aligned with a cavity mode formed by the first and second reflector.

A semiconductor laser element is a semiconductor laser element that emits laser light, and the semiconductor laser element includes a substrate, a first semiconductor layer above the substrate, a light emitting layer above the first semiconductor layer, a second semiconductor layer above the light emitting layer, and a dielectric layer above the second semiconductor layer. The second semiconductor layer includes a waveguide that guides the laser light. A width of at least a portion of the waveguide is modulated with respect to a position in a direction of resonator length, the direction being a longitudinal direction of the waveguide. The waveguide includes a first waveguide and a second waveguide that is wider than the first waveguide. A difference between an effective index of refraction inside the waveguide and an effective index of refraction outside the waveguide is greater in the second waveguide than in the first waveguide.

Provided is a semiconductor laser element including: a resonator structure; and a first reflection film and a second reflection film provided on a non-emission end surface of the resonator structure and an emission end surface of the resonator structure, respectively. Reflectance R of the second reflection film at a gain wavelength satisfies the following relational expression: R1≤R≤R(Oc)×C where R1 is reflectance of the second reflection film when the resonator structure performs laser oscillation with power 1.4 times a minimum value of threshold power which is minimum power for the resonator structure to perform the laser oscillation, R(Oc) is reflectance of the external resonance mirror, and C is a ratio of light, which is reflected by the external resonance mirror and is incident in the resonator structure, to light which is reflected by the external resonance mirror.

A Vertical Cavity Surface Emitting Laser (VCSEL) including a light emitting III-nitride active region including quantum wells (QWs), wherein each of the quantum wells have a thickness of more than 8 nm, a cavity length of at least 7 λ, or at least 20 λ, where lambda is a peak wavelength of the light emitted from the active region, layers with reduced surface roughness, a tunnel junction intracavity contact. The VCSEL is flip chip bonded using In—Au bonding. This is the first report of a VCSEL capable of continuous wave operation.

A controller stabilizes a distributed feedback plus reflection (DFB+R) laser, which has a back facet, a DFB section, a passive section, and a front facet with a low reflective element. An etalon filter is formed by a portion of the DFB section, the passive section, and the low reflective element. Control circuitry directly modulates the DFB section with a modulation signal and biases the passive section with a bias signal. In operation, a lasing mode of the DFB section is aligned to a long wavelength edge of one of the periodic peaks of a reflection profile of the etalon filter. Meanwhile, photodiodes are arranged to monitor the output power emitted from the laser's front and back facets. The control circuitry monitors a ratio of the detected output power and adjusts the bias based on the monitored ratio.

Materials containing picocrystalline quantum dots that form artificial atoms are disclosed. The picocrystalline quantum dots (in the form of born icosahedra with a nearly-symmetrical nuclear configuration) can replace corner silicon atoms in a structure that demonstrates both short range and long-range order as determined by x-ray diffraction of actual samples. A novel class of boron-rich compositions that self-assemble from boron, silicon, hydrogen and, optionally, oxygen is also disclosed. The preferred stoichiometric range for the compositions is (B.sub.12H.sub.w).sub.xSi.sub.yO.sub.z with 3≤w≤5, 2≤x≤4, 2≤y≤5 and 0≤z≤3. By varying oxygen content and the presence or absence of a significant impurity such as gold, unique electrical devices can be constructed that improve upon and are compatible with current semiconductor technology.

A radiation source for emitting terahertz radiation (6) is specified, comprising at least two laser light sources emitting laser radiation (11, 12) of different frequencies, and a photomixer (5) comprising a photoconductive semiconductor material (51) and an antenna structure (52), the photomixer (5) being configured to emit the laser radiation (11, 12) of the laser light sources (1, 2) and emitting terahertz radiation (6) with at least one beat frequency of the laser light sources, and wherein the at least two laser light sources are surface-emitting semiconductor lasers (1, 2) which are arranged in a one-dimensional or two-dimensional array on a common carrier (10).

A light-emitting element includes: a laminated structure body 20 which is formed from a GaN-based compound semiconductor and in which a first compound semiconductor layer 21 including a first surface 21a and a second surface 21b that is opposed to the first surface 21a, an active layer 23 that faces the second surface 21b of the first compound semiconductor layer 21, and a second compound semiconductor layer 22 including a first surface 22a that faces the active layer 23 and a second surface 22b that is opposed to the first surface 22a are laminated; a first light reflection layer 41 that is provided on the first surface 21a side of the first compound semiconductor layer 21; and a second light reflection layer 42 that is provided on the second surface 22b side of the second compound semiconductor layer 22. The first light reflection layer 41 includes a concave mirror portion 43, and the second light reflection layer 42 has a flat shape.